An online surveillance tool that analyzes Internet data is able to identify places in real time were public fear about vaccines is on the rise, researchers report, and may be able to nip vaccine misinformation in the bud before it blooms.

Heidi Larson, PhD, of the London School of Hygiene and Tropical Medicine in England, and colleagues have adapted HealthMap, an automated data collection system usually used to track disease outbreaks, to monitor online sentiments about vaccines.

From May 1, 2011 to April 30, 2012, HealthMap identified 10,380 online mentions of human vaccines, vaccination campaigns and vaccination programs in 144 countries.

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Overall, 31% of reports were negative and consisted of fears about adverse events and distrust of the vaccine industry. The rest of the reports were either positive or neutral.

Among the 3,209 negative reports, 24% focused on vaccination programs and disease outbreaks, whereas 21% expressed attitudes about vaccine beliefs, awareness and perceptions. Vaccine safety and vaccine delivery programs accounted for 16% each of the total negative reports.

In contrast, 33% of all positive reports focused on vaccine development and introduction, whereas just 3% expressed attitudes regarding vaccine beliefs, awareness and perceptions.

“The Internet has speeded up the global spread of unchecked rumors and misinformation about vaccines and can seriously undermine public confidence, leading to low rates of vaccine uptake and even disease outbreaks,” Larson said  in a press release.

She and colleagues hope that systems such as HealthMap can help identify early signs of vaccine misinformation, so that public health officials can act immediately to dispel unfounded fears.

Although the current study was unable to assess the long-term predictive value of HealthMap, it enables researchers to categorize online vaccine information by “topic, negative or positive content, location, time and risk level,” in real time, according to the researchers.

In an accompanying editorial, Natasha Sarah Crowcroft, MD, of Public Health Ontario, and Kwame Julius McKenzie, MD, of the Centre for Addictions and Mental Health, both in Toronto, called vaccine safety concerns promoted in social and news media the “biggest threat facing the success of immunisation.”

“Public health systems need to move beyond passive responses to vaccine safety events towards active preparedness,” they wrote, adding it is important for researchers to discover how to make communities “resilient to bad science and interest-driven scare stories.”


  1. Larson HJ et al. Lancet Infect Dis. 2013: doi: 10.1016/S1473-3099(13)70108-7.
  2. Crowcroft NS, McKenzie KJ. Lancet Infect Dis. 2013; doi: 10.1016/S1473-3099(13)70131-2.